Colored textile materials and method of producing same



Patented Apr. 2, 1940 I UNITED STATES COLORED TEXTILE MATERIALS ANDMETHOD OF PRODUCING SAME George W. Seymour and Victor Sluyty Salvin,

Cumberland, Md., assi poration of America, ware No Drawing. Applicatignors to Celanese Cora corporation of Delaon February 11, 1938,

Serial No. 190,041

10 Claims.

This invention relates to the production of dark colored textilematerials that are made of or contain organic derivatives of celluloseand, more particularly, to the method of producing a dark color in or onsuch textile materials.

An object of this invention is the economic and expeditious productionof black-dyed fabrics and other textile materials made of or containingorganic derivatives of cellulose, the coloration being effected byapplying a diazotizable dyestuff base to the material, diazotizing andcoupling with a naphthoic or similar acid. Another object of thisinvention is the production of black fabrics or other textile materials,made of or containing organic derivatives of cellulose, that do notcrock or bleed and that are more fast to acid and light fading thanfabrics dyed by methods employed prior to this invention. Other objectsofour invention will appear from the following detailed description.

By employing this invention, there is effected an improvement both inreducing crocking and/ or bleeding and a more uniform standard shade isobtained. In accordance with this invention, there are produced blackfabrics containing. organic derivative of cellulose yarns that do notbleed pink when rubbed with a similar but undyed fabric wet withperspiration nor :crock black when rubbed with a dry white fabric.Forthe purpose of describing this invention the term crocking will beused as including bleeding or other forms of dyeing defects that allowthe black fabric to color white fabric. attached thereto when the twofabrics are washed, dry cleaned, subjected to perspiration, acid fumesor rubbing.

By employing this invention, there is also produced a black fabriccontaining organic derivative of cellulose yarns that is more fast toacid fading and light fading than similar black fabrics produced priorto this invention. The sta-' bility of the dyed fabric is extremely goodmaking it exceptionally well suited as a lining fabric for coats orother wearing apparel.

It is known thatthere are three major forms of crocking of; fabriccontaining organic derivatives of cellulose that are dyed black withdiazotized dyestufis. First, and least desirable, is a pink-to-redcrocking which appears to vary in intensity with different batches ofdyed fabric. The tendency of this type of pink-to-red crocking is tobleed off from a coat lining fabric when wet with perspiration. Crockingin another form is evidenced as a black coloration which also appears tovary in intensity with different batches,

with different qualities of fabric and with the same quality of fabricwhich has been processed in two batches by apparently identical means.The third form of crocking appears as an oily black substance which isready removable by thorough scouring, which scouring, however, issometimes required to be more severe than fabrics containing organicderivatives of cellulosecan withstand. We have found that by employingthis invention, these types of crocking can be eliminated orsubstantially eliminated without the addition of costly reagents oradditional processing steps. At the same time a more stable fabric isproduced that has a faster color.

In accordance with this invention, we apply a diazotizable black dyebase to a fabric containing an organic derivative of cellulose anddiazotize the base in the presence of an excess of mineral acid(preferably HzSO4, HCl or mixtures of these) for each amino group to bediazotized. The excess of mineral acid is preferably about mol excess ofmineral acid per amino group to be diazotized. Since the mineral acidmust be removed prior to coupling, preferably by washing, we have foundthat not more than a few ends in a jig at 25 C. or its equivalent in awench should be used instead of the customary large number of ends. Inorder to remove all of the mineral acidfrom the fabric the bath shouldcontain sodium acetate, sodium bicarbonate or other soluble neutralizingsalts. Where sodium acetate is employed in the bath, better shades areobtained and pink-to-red crocking is substantially eliminated. Thewashing should be carried out by a process which avoids exposure of thediazotized fabric to light, air, heat, etc. and which removes the excessacid rapidly. After washing to remove excess acid the diazotized fabricis coupled with a suitable coupling compound, preferably,B-oxy-naphthoic acid. In order to decrease the decomposition productscaused by side reaction in the coupling process, the diazotized fabricmust be coupled soon after diazotization has been completed. Thetemperature and pH value of the coupling bath must be closely controlledwhile the accessibility of the coupling compound to the fabric and thethorough adsorption of the coupling compound into the fabric must beobserved. The coupling operation should be performed by runmng thefabric two or three ends at 20 C. in'a jig or its equivalent on a wenchto promote efficient adsorption and then 1 to 3 ends at 38 C. to 42 C.to promote coupling with a final end at about C. to C. to acceleratecoupling and to decompose any remaining azo group. The coupling compoundis dispersed in the treating bath with the aid of dispersing agents withsufllcient buffer salts (preferably sodium acetate or sodiumbicarbonate) to maintain the pH value of the bathat between 5 to 7. Thecoupling compound couples best at about a pH value of 7 or higher, butthen it is present as a metallic salt which is not readiLv adsorbed bythe fabric. Therefore, the pH value should be "I or slightly below,.preferably between 5 and 7. g

This invention is applicable to yarns, fibers, ribbons, straws, etc.,but more especially to fabrics made of or containing organic derivativesof cellulose such as the organic esters of cellulose, mixed esters ofcellulose and the cellulose ethers. Examples of the organic esters ofcellulose are cellulose acetate, cellulose formate, cellulose propionateand cellulose butyrate, while examples of the cellulose ethers are ethylcellulose, methyl cellulose and benzyl cellulose.

The fabric to be treated may be made wholly of organic derivative ofcellulose material or it 1 terial may be aniline-4-azo-4-a-naphthylamineor analogues of the same which when coupled with a suitable couplingagent produces a dark color. Suitable analogues and the color theyproduce when coupled with p-oxy-naphthoic acid arephenol-4-azo-4-a-naphthylamine (bl u is h .black) benzene-i-azo-ia-naphthylamine (reddish black), para-methoxy-benzene-azo-a-naph- 40'.

.thylamine (bluish black of very good depth), ortho methoxzybenzene azoa naphthylamine (purplish' black) and naphthalene-azo-a-naphthylamine(slightlyreddish black).

The coupling compound is preferably p-oxynaphthoic acid or its analogueswhich produces a black or substantially black color on the fabric.However, the invention is also applicable where coupling compounds thatproduce a blue color or a red color or combinations of these colors areemployed. Examples of such coupling compounds are a-naphthoh,p-naphthol, phenol,- salicylic acid and their derivatives orsubstitution products.

It has been customary in the past when applying the dye base and formingthe diazonium compound to employ a mixture of formic-hydroformed in thepresence of an organic acid decomposes markedly at 30 to 40 0. whereasthediazonium salts produced in the presence of hydrochloric, sulphuricor other mineral acid is relatively stable up to 50 to 60 0. Thus, whereinorganic acids alone are employed, there is not only produced a moreuniform shade on the fabric but there is also permitted a greater rangeof temperature in future processing steps. The

use of mineral acids only promotes the possi-- bility of more completediazotization. When sufficient mineral acid is used diazotization isbetween and complete, provided, how- 1 ever, that there is an excess ofthe mineral acid employed. For instance, when diasotizinganiline-4-azo-4-a-naphthylamine l1 mols of the dye base are employed,and 42 mols of sodium nitrite and 44 mols of hydrochloric acid or itsequivalent are the absolute minimum necessary for completediazotization. For improved results to be derived in accordance withthis invention the presence of an excess of mineral acid is required.This excess should be about mol of acid per amino group. Where excessacid less than this quantity is-employed, it has been found that thereis a tendency towards sluggish reaction and incomplete diazotization.The excess acid, however, may be from about mol to 1 mol excess of acidper amino group to be diazotized. Due to the excess acid present duringthe diaaotiliation step it is preferable to maintain the temperature-at'between 5 to 10 C. with ice or artiiicial cooling means to preventinjury to the dyestufl', fabric or machine and to the operator due tothe evolution of acid fumes. The temperature may be allowed to raise toabout-50 C. When sulphuric acid is employed since the diazonium,sulphate is stable up to about60 C.

With other mineral acids other maximum temperatures would apply., The 42mols of nitrite is; of course, not the theoretical quantity necessarytoreact with llmols of dye base, as 22 mols would be. suiiicient. Thisexcess quantity is based on the empirical evidence that this quantitygives the best results for complete diazotization.

The large excess is in part necessitated in order to maintain theequilibrium for nitrous acid formation under the conditions present.

After diazotization it is necessary to subject the fabric toa washingprocess in order to remove the excess inorganic acid. This is neces-.

sary for two major reasons, one to prevent the precipitation of thecoupling compound as a nonreactive. material and, second, to enable thecoupling to proceed thoroughly and uniformly. The diazonium salts of theinorganic acid must be hydrolyzed to the diazohydrate in order for it tocouple at a reasonable rate. The diasotized fabric n ust be washedthoroughly. and quickly without exposure to air, light or heat. Exposure7 of the fabric produces an irreversible decomposition of the diazoniumcompound which, after it occurs, greatly increases the tendency oi -thedyed fabric to crock. The amount of dye'base applied to the fabric maybe any suitable amount, say from 0.1 to 6% by weight of the fabric.

After the dye base has been applied to the fabric and the fabric washedfree of excess mineral acid, the fabric issubjected to an operationincluding the application thereto of a coupling compound undersuchconditions that the coupling compound reacts with the diam-compound.

formed from the dye base. The- 'coupling reaction must always be lookedupon as a race between azo compound formation and decomposition of thediazo compound. Some diazonium compounds are so sensitive. to thisfactor that rigid control of the pH value of the treating bath isnecessary 'to obtain consistent results sorbed on the fibers it must bepresent as an 7 In this respect the acid. Obviously, therefore, the pHvalue of the aqueousdispersion of the coupling compound must be below'7, preferably between 5 and '7, as below this'point an adsorptionreadily takes place but coupling is sluggish and acid reaction compoundsare formed.

In the coupling operation the temperature of the treating bath must alsobe controlled in order to produce an improved dyeing and a uniform shadefrom batch to batch. In order to decrease the decomposition productsfrom side reactions to the coupling process the diazotized fabric mustbe subjected to the coupling reagent immediately after diazotization hasbeen completed. The temperature of the bath at the time the fabric issubjected thereto is preferably around 20 C. for at this temperature theadsorption of the coupling compound by the fabric is greatlyfacilitated. The temperature should then be raised to about 40 C. topromote coupling and retard decomposition, blackening of the fabric, dueto coupling, does not occur until this temperature has been reached. Thetemperature should then be rapidiy raised to above 60 C.. preferablybetween 60 and 75 0., to accelerate coupling and to decompose theremaining azo groups. For instance, when dyeing the fabric on a jig thefabric is run two ends at 20 C. to permit thorough incorporation of thep-oxynaphthoic acid in the fiber, two ends at 40 C. for at thistemperature coupling starts, then two ends at 70 C. in order to completethe coupling of the sluggish reaction. The. high temperature should beavoided initially since decomposition of the diazonium compound of thedye base is accelerated at those temperatures.

The bath from which the coupling compound is appliedto the fabric ispreferably formed by dispersing the coupling compound in a dispersingagent approaching neutrality and well buffered with such salts assodiumacetate or sodium bicarbonate for changes in pH value. It is knownthat if the particle size of the coupling compound is controlled by theuse of a dispersing agent a great reduction in the amount of crocking ofthe dyed fabric is obtained. The use of the dispersing agent isimperative also in that it controls the particle size and disperses thecoupling materials which form the coupling bath, thus making a moreuniform and thorough penetration of the coupling compound into thefabric. This dispersion also prevents the superficial formation of thedye on the outside of the fabric and also to the deposition ofnondispersible compo-ands adhering to the fabric from the couplingprocess. Obviously the dispersing agent should have no reaction with thecoupling compound. Suitable dispersing mediums which may be employedwith the coupling compounds listed above are a mixture of Turkey red oiland xylol, the sodium salt of sulphated lauryl alcohol or other higherfatty alcohol, sulphonated vegetable oils, dextrin, sulphated naphtheneand similar dispersing mediums or mixtures of the same.

In order to further illustrate our invention, but without being limitedthereto, the following example is given:

EXAMPLE This example is for jig dyeing. A typical charge is 150,000grams of fabric. By one end" is meant one pass through the dye solutionwithout regardto difierential in speed and time due to the change indiameter of the fabric on the beam. At normal speeds one end would takefrom 20 to 30 minutes. A typical Black dyeing on the jig would use thefollowing quantities:

, Rinse 2 ends cold; 2 ends at 90 C.-to set the fabric to the 118.

Basing Fabric grams 150,000 Water liters 500 Black dyebase gramsSulphonated naphthalene ricinoleic acid ..do Gardinol do 2,600 Soda ashdo 800 Temperature, 90 C.; time, 50 ends= 1000 min.

scouring Gardinol grams 3,000 Soda ash do Water liters.. 500

Temperature, 90 C.; time, 10 ends=200 min.

Diazotization Water -1 liters Sodium nitrite grams H2804 ccs 2,000

Temperature, iii-22 C.; time, 4 ends= min.

Wash

Cold water liters 500 (Sodium acetate optional) grams 500' (ResidualHNO2 or HCl negligible.)

Temperature, 18-20 C.; time, 2-3 ends= 40-60 min.

This bath should have a pH of 6-6.5 and should not change materiallyduring processing.

Wash

Washing may be carried out with either hot or cold water in order tofree the fabric from the ingredients of the coupling bath.

With regard to the amount of water retained in the fabric before,between and after each processing step, the fabric is at all timesthoroughly wetted out after the initial step of setting to the jig. Theamount'of water retained by the fabric will probably be between two andfive times the weight of the fabric, depending upon the type of fabric,weave, twist, and whether or not it was mixed with cotton, viscose,silk, etc.

. The fabric after drying is found to be colored a good black and to beexceptionally fast to light and acid-alkali or perspiration fading. Thechemical stabilityjof the organic derivative of cellulose in the fabricis found to be substantially as good as the stability of the undyedmaterial. It is to be understood that the foregoing detailed descriptionis merely given by way of illustration and that many variations may bemade therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by LettersPatent is:

. 1. Process .for the production of 'dark colored textile materialscontaining organic derivatives.

of cellulose by a process employing diazotizable 15 dyestufl's, whichcomprises applying a diazotizable dyestufi' base to said textilematerials, diazotizing said dyestufi base, washing the treated textilematerials with water until the diazonium salt formed is hydrolyzed tothe diazohydrate, and couplind with a coupling component producing adark color on said textile materials.

2. Process for the production of dark colored textile materialscontaining cellulose-acetate by a process employing diazotizabledyestufls, which comprises applying a diazotizable dyestuff baseto saidtextile materials, diazotizing said dyestufi base, washing the treatedtextile materials with water until the diazonium salt formed ishydrolyzedto the diazohydrate, and coupling with a coupling componentproducing a dark color on said textile materials.

3. Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestuffs, which comprises applying a diazotizabledyestuflf base to saidtextile materials, diazotizing said dyestuif base in the presence of anexcess of mineral acid, washing the treated textile materials with wateruntil the diazonium salt formed is hydrountil the diazonium salt formedis hydrolyzed to the diazohydrate, and coupling with a couplingcomponent producing a dark color on said textile materials.

5. Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestuifs, which comprises applying a diazotizable dyestufi base tosaidtextile materials, diazotizing said dyestuil base in the presence ofan excess of mineral acid, washing the treated textile materials withwater for 40 to 60 minutes to hydrolyze the diazonium salt formed to thediazohydrate, and coupling with a coupling component producing a darkcolor on said textile materials.

6. Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestufis, which comprises applying a diazotizable dyestufi base to saidtextile materials, diazotizingsaid dyestufi base in the presence of anexcess of mineral acid, washing the treated textile materialswith waterfor 40 to 60 minutes inthe presence of sodium acetate to .hydrolyze thediazonium salt formed to the diazohydrate, and coupling with a couplingcompat ent-producing a dark color on said textile materials.

7. Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestufis, which comprises applying ,a diazotizable dyestufl base tosaid textile materials, diazotizing said dyestufl base in the presenceof an excess of mineral acid, washing the treated textile materials withwater for 40 to 60 minutes in the presence of sodium acetate tohydrolyze the diazonium salt formed pH value is maintained at between 5and 7.

8. Process for the production dark colored textile materials containingorganic derivatives of cellulose by a process employing diazotizabledyestufis, which comprises applying a diazotizable dyestufi base "tosaid textile materials, diazotizing said dyestufl base inthe presence ofan excess of mineral acid, washing the treated textile materials withwater for 40 to 60 minutes in the presence of sodium acetate tohydrolyze the diazonium salt formed to the diazohydrate, and couplingwith ,s-oxy-naphthoic acid in a coupling bath in which the pH value ismaintained at be-. tween and 7.

9.- Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestufls, which comprises applying a diazotizable dyestufi base to saidtextile materials, diazotizing said dyestufl! base in the presence of anexcess of mineral acid,

washing the treated textile materials withwater' for 40 to 60 minutes inthe presence oi. sodium acetate to hydrolyze the diazonium salt formedto the diazohydrate, and coupling with p-oxynaphthoic acid in a couplingbath in which the pH value is maintained at between 5 and 7.

10. Process for the production of dark colored textile materialscontaining cellulose acetate by a process employing diazotizabledyestufis, which comprises applying a diazotizable dyestufi base to saidtextile materials, diazotizing said dyestufl base in the presence of anexcess of mineral acid, washing the treated textile materials with waterfor 40 to 60 minutes in the presence of sodium acetate to hydrolyze thediazonium salt formed to the diazohydrate, and coupling withp-oxynaphthoic acid dispersed with the aid of a dispersing agent in anaqueous bath in which the pH value is maintained between 5 and 7.

GEORGE W. SEYMOUR. VICTOR SLUY'I'Y SALVIN.

.tile materials in a coupling bath in which the CERTIFICATE OF coREcTio'N.

P a-tent No. 2,195,585. April 2, 19M).

v GEORGE W'. SEYMOUR, AL} It' is hereby Certified that error appears inthe printed specification of the above numbered patent requiringcorrection he follows: Page 5, secend column,1:Lne 15, in the table,ffor Gardinol- --db---2, 600" read --.Ga.rd1nol--- io---,OOO-- page 1;,first column; line 6; claim 1, for couplind read :oupl1ng--;

and that the s eid Letters Patent should. :be read with this-correctiontherein that the Same may cenferm to the record of the case in thePatent Office.

Signed andeealed thielhth day of May, A. D. 19, 0.

, Henry Vggm Arsdaie, (Seal) Acting Commissioner of Patents.

